The main theme is the continuation of earlier work on several aspects of the regulation of metabolic processes. The specific problems to be studied are: (1) the elaboration of techniques employing isolated cells as experimental materials in metabolic studies (hepatocytes, intestinal mucosa, mammary gland, salivary gland); (2) the mechanism of the involvement of methionine in the degradation of formiminoglutamate derived from histidine; (3) regulation of glutamine metabolism, especially the relative roles of intestinal mucosa and liver in the degradation of glutamine; (4) the regulation of the adenine nucleotide content of animal tissues, starting from the observation that addition of adenosine can increase the hepatic adenine nucleotide content up to 4 fold; (5) the metabolic response of humans to trauma (accidental injury) with the objective of preventing nitrogen loss; (6) variations in the amino acid pool of erythrocytes in diseases. The main experimental material will be isolated cells and perfused organs, in combination with the determination of metabolites in vivo by the freeze clamping technique. The chief experimental animal will be the rat. In collaboration with clinicians items (5) and (6) will include studies on humans.